Supercharged111
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It's because the govt is r3ta@rded and can't make sane rules. Or maybe it's because they know D students are gonna be the ones to enforce them.
Quieter upgrade?
- Thread starter NMNorsse
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It's because the govt is r3ta@rded and can't make sane rules. Or maybe it's because they know D students are gonna be the ones to enforce them.
L31MaxExpress
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Regardless if it is enforced in a local jurisdiction it is still a federal law. Look at how many tuning shops and companies the EPA has fined millions of $$$ to lately. The fine to Cummins was 1.675 Billion with a B.
L31MaxExpress
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This is how I am approaching the L31 in the 87 G20. Sticking with an OE L31 like exhaust configuration given that is what the engine more or less is. Also makes it easier to put a L31 manifold and PCM on it in the future should the need arise for the future. I could always add 4 02 sensors, a GMT400 charcoal canister with a functioning purge valve and vent valve and pressure sensor as well. I know for a 100% fact the sequential port fuel injection paired with the 3 way heavy load ceramic core OBD2 cats will run far cleaner than the 305 TBI ever did with GMs ancient pelletbox cat, wet flow TBI manifold and archaic 7747 TBI computer. The 3 way cats will reduce NOx emissions far better than the EGR ever did as well. Edelbrocks wideband kicks in immediately and starts trimming the fuel delivery seconds after the engine starts even dead cold. Even though Edelbrocks system was not intended to be CARB complient I am sure it will run cleaner than any L31 with the black box and poppets ever thought about running. I also always keep the charcoal cannister on anything I build. Never will understand why people want to delete such a passive emissions device that actually ends up slightly improving their fuel mileage by capturing and burning those fumes that would otherwise be vented to the atmosphere or the inside of your shop or garage.
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Supercharged111
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Somebody watched Pentagon Wars.
Locally exempt from TESTING.
FEDERAL law says you can't tamper/disable the emissions devices. If the Feds want you, you've given them a way to do it. (They got Capone for tax evasion, not murder.) Functionally, the Feds don't do emissions testing or enforcement (yet, unless they have specific reason for jerking someone around) so you'd probably get by with it.
True.
1. Half the exhaust flow through double the catalyst. Takes way longer for the cat to get hot enough after a cold start. Until the catalysts fully warm-up, they're ineffective.
Same reason you're now seeing catalysts built right into the exhaust manifold--exhaust gas is the hottest, lights-off the catalyst faster than if it was downstream. (Also makes the cat harder to steal.)
2. Catalysts run hot by nature. If you move the catalyst from where the OEM heat-shielding is, you could set fire to the carpet. This was a bigger problem when the catalysts didn't come with the heat shielding already attached, and the floor pans were stamped to provide extra clearance for one catalyst...but "the law is the law".
And Toyota spend the money to have that system certified for emissions compliance and safety. You're not spending the millions of dollars for the certification.
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L31MaxExpress
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While I agree on the catalyst warm up being quicker the closer it is to the engine, some GM vehicles in the 80s and 90s had the catalytic converter after the muffler. There were also some setups that had an additional catalytic converter near the tailpipe. There were others like my Express van that came with a resonator ahead of the RH catalytic converter for some odd reason. I have also seen later model GM stuff factory built without cats and rear 02 sensors, actually quite common on the 8.1L trucks. I have seen some 5.7L, 7.4L and 4.8L and 6.0L vehicles built without cats or even with cats and no rear 02s as well. I read the OE calibration on that 6.0L and it had all the rear 02 stuff and catalyst efficiency disabled. The tune had all the right CVN values for the VIN.
I was under an 02 5.7L Express van a few months back at the wrecking yard that had the OEM y-pipe in it, 2 front 02s, no cats and no rear 02s. I actually looked it up and it was an OE GM exhaust system. Still will never understand where in the USA they allowed those to be sold. Then again it was a dedicated CNG van without a gasoline fuel system, so maybe those were catless. My 2003 Sonora (GMT800 Tahoe) was factory cat deleted but it was a Mexican build. This van had a federal emissions sticker on it. Actually kind of wonder if that van was one of the US government purchases like the new factory deleted diesel trucks they are buying from Ford. Have to love the US government, attack Cummins yet demand Ford to build their trucks deleted.
I was under an 02 5.7L Express van a few months back at the wrecking yard that had the OEM y-pipe in it, 2 front 02s, no cats and no rear 02s. I actually looked it up and it was an OE GM exhaust system. Still will never understand where in the USA they allowed those to be sold. Then again it was a dedicated CNG van without a gasoline fuel system, so maybe those were catless. My 2003 Sonora (GMT800 Tahoe) was factory cat deleted but it was a Mexican build. This van had a federal emissions sticker on it. Actually kind of wonder if that van was one of the US government purchases like the new factory deleted diesel trucks they are buying from Ford. Have to love the US government, attack Cummins yet demand Ford to build their trucks deleted.
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Buddy of mine has an early-'90s Ford 3/4 ton truck with a sticker on the rad shroud saying it's catalyst-exempt. Of course he thinks this makes the truck worth a fortune and can't understand why it won't sell.
I have heard of that--the Feds allowed farmers and the Forest Service, for example, to remove the catalysts on "field trucks" so the hot catalyst didn't set fire to grasslands. But for all I know, his sticker is something out of somebody's imagination, with a random "certification number" written on it.
And of course the Military gets whatever they want because of "National Security".
Maybe if you go up high enough in GVWR, an 8.1 can run clean enough to not need a cat or downstream sensors...seems goofy to me.
My '80 Honda Civic 1300 did not have a converter, but the 1500 engine did.
Moral of the story is that if you can get it certified by an EPA- or CARB-accredited facility, you can run it. If someone else gets it certified on a vehicle similar-enough to yours, you can run it. Driveway Engineering of emissions systems isn't allowed.
I have heard of that--the Feds allowed farmers and the Forest Service, for example, to remove the catalysts on "field trucks" so the hot catalyst didn't set fire to grasslands. But for all I know, his sticker is something out of somebody's imagination, with a random "certification number" written on it.
And of course the Military gets whatever they want because of "National Security".
Maybe if you go up high enough in GVWR, an 8.1 can run clean enough to not need a cat or downstream sensors...seems goofy to me.
My '80 Honda Civic 1300 did not have a converter, but the 1500 engine did.
Moral of the story is that if you can get it certified by an EPA- or CARB-accredited facility, you can run it. If someone else gets it certified on a vehicle similar-enough to yours, you can run it. Driveway Engineering of emissions systems isn't allowed.
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Got to disagree with that. Manifolds be they headers or cast logs have nothing to do with how much sound exits out the back. The sound waves are contained within the pipe. 151 S-10's and 302 Ford Mustangs came from the factory with SS round tube header type manifolds and they were no louder than comparable vehicles with iron log manifolds. The stangs had a little exhaust note by design. Long tube headers will ring at certain frequencies,normally under WOT but it's not loud,to me it's music.
Is there any difference between the Mexican Sonora and US Tahoe?
Not exactly. We just got a lot of stuff grandfathered in because it would cost billions to replace it all. They're still running Hobart generators on the flightline with 4-72 Detroits in them, but that's because the company making the replacement generators with 6BT Cummins keeps getting busted for not meeting production deadlines and not having enough spares on hand. It's turned into a $#!+show.
Refueling trucks don't have cats, but they also have all the exhaust mounted at the front bumper of the truck. They're exempt for safety reasons, much like forestry trucks.
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